Commercial thinning in western hemlock (EP 388)

Last updated on August 22, 2023

Introduction

E.P. 388 was established in 1953 by C. Joergensen of the B.C. Forest Service in a western hemlock stand located on East Thurlow Island, about 50km north of Campbell River, B.C. The stand originated from natural regeneration following clearfelling of old growth in 1894 and slashburning in 1896, making it one for the oldest second-growth western hemlock stands in the province. The study was to determine growth response and potential (utilization) and profit from thinning immature western hemlock stands.

Objectives

To study the effects of repeated thinning of different intensities on stand and tree characteristics.

Treatments

The experiment was established in 1953 in a 55-year-old naturally-regenerated Western hemlock stand at East Thurlow Island. The treatments were defined in terms of residual basal area from very light to very heavy thinning: no thinning (control), thin to 51.7 m²/ha, thin to 45.9 m²/ha, thin to 40.2 m²/ha, and thin to 34.4 m²/ha using a d/D ratio of 0.85. The five treatments are replicated four times in 0.4 acre (0.1619ha) plots surrounded by a 10- to 20-m wide buffer strip between adjacent plots. The plots were bocked by initial (pre-thinning) basal area.

Status

Active

Publications

Omule, S.A.Y. 1989. Growth and yield 32 years after commercially thinning 56-year-old western hemlock. Can. For. Serv. and B.C. Min. For., Victoria, B.C. FRDA Rep. 029.

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